Arrays Linked Lists Questions Medium
The main difference between a stack and a queue in terms of implementation lies in the way elements are added and removed from the data structure.
A stack is a Last-In-First-Out (LIFO) data structure, meaning that the last element added to the stack will be the first one to be removed. It can be implemented using either an array or a linked list.
When implementing a stack using an array, a fixed-size array is typically used, and a pointer called "top" is used to keep track of the topmost element in the stack. Elements are added to the stack by incrementing the top pointer and placing the new element at the corresponding index in the array. Similarly, elements are removed from the stack by accessing the element at the top index and then decrementing the top pointer.
On the other hand, when implementing a stack using a linked list, each element in the stack is represented by a node, which contains the actual data and a reference to the next node. The top of the stack is represented by the head node of the linked list. Elements are added to the stack by creating a new node and updating the next reference of the new node to point to the current top node. Elements are removed from the stack by updating the head node to point to the next node in the linked list.
A queue, on the other hand, is a First-In-First-Out (FIFO) data structure, meaning that the first element added to the queue will be the first one to be removed. Similar to a stack, a queue can also be implemented using either an array or a linked list.
When implementing a queue using an array, a fixed-size array is typically used, and two pointers called "front" and "rear" are used to keep track of the front and rear ends of the queue, respectively. Elements are added to the queue by incrementing the rear pointer and placing the new element at the corresponding index in the array. Elements are removed from the queue by accessing the element at the front index and then incrementing the front pointer.
When implementing a queue using a linked list, each element in the queue is represented by a node, similar to a stack. However, in a queue, the front and rear pointers are used to keep track of the head and tail nodes of the linked list, respectively. Elements are added to the queue by creating a new node and updating the next reference of the current tail node to point to the new node, and then updating the rear pointer to the new node. Elements are removed from the queue by updating the head node to point to the next node in the linked list.
In summary, the main difference between a stack and a queue in terms of implementation is the order in which elements are added and removed. A stack follows the Last-In-First-Out (LIFO) principle, while a queue follows the First-In-First-Out (FIFO) principle.